This invention relates to composite-link rear axle arrangements having a flexurally rigid and torsionally resilient transverse member and a longitudinal member attached to each end of the transverse member by a plug connection in which each longitudinal member is adapted to receive a wheel carrier at one end and to be articulated to a vehicle body at the other end.
A conventional composite-link rear axle arrangement disclosed in German Offenleguengsschrift No. 44 41 971 has a transverse member and two longitudinal members which are attached to the respective opposite ends of the transverse member. In this arrangement, the longitudinal members are appropriately designed at one end to receive a wheel carrier and at the other end for articulation to a vehicle body. In addition, the transverse member is designed to be flexurally rigid but torsionally resilient and the longitudinal members are connected to the transverse member so that a stabilizer effect can be achieved with respect to the compression and expansion movements of the wheels, permitting the transverse and longitudinal forces acting on the vehicle wheels to be absorbed by the entire composite-link rear axle. Usually, the transverse member and each longitudinal member are produced from an aluminum alloy, the opposite ends of the transverse member being plugged into corresponding recesses in the longitudinal members which are provided for this purpose. The plug connections thus made between the transverse member and the longitudinal members are then rigidly attached by an appropriate method such as by adhesive bonding, welding, riveting or appropriate shaping. This attachment technique may vary depending, in particular, on whether the transverse member is designed, for example, as an extruded part with a semi-open profile and whether the longitudinal member is a casting or has a ribbed extruded shape.
Such conventional composite-link rear axle arrangements do not have the best possible design. In general, the outer regions of the transverse member are designed so that they are received in a groove-like guide of the corresponding longitudinal member. Since the traverse member is made of a light metal having a substantially lower modulus of elasticity than that of steel, the flange width of the light-metal profile of the transverse member must be extremely large in the outer region if a predetermined torsional rigidity is to be ensured. Consequently, when torsion occurs in use there is a correspondingly pronounced cambering of the outer regions of the transverse member flange regions. This cambering causes the outer flange regions of the transverse member to be displaced in the direction transverse to the vehicle, referred to herein as a Y axis displacement, which is sometimes very pronounced. Since the outer regions of the transverse member which are plugged into the longitudinal member are generally firmly clamped in the direction of the vehicle transverse axis i.e., the Y-direction, by a welded joint, or by screws, or the like, the torsional rigidity of the transverse member is increased undesirably. The result is that, because of this high rigidity, the stabilizer effect to be achieved is likewise too high.